Portable scaffold

ABSTRACT

Described herein is a portable, vertically adjustable, scaffold. This scaffold comprises a base, a telescoping mast hingeably attached thereto and a platform. The telescoping mast is raised by a hydraulic hoist and the mast is rotated about its lower end with a hydraulic hoist. As the telescoping mast is raised, a cable secured to the mast raises the platform assembly along the mast. Outriggers are provided to add stability to the scaffold.

United States Patent Meinecke, Jr.

[451 May 30, 1972 PORTABLE SCAFF OLD Clarence A. Meinecke, Jr., 306South Pinet, Jefferson. lowa Filed: Jan. 19, 1971 Appl. No.: 107,764

Inventor:

3,344,885 10/1967 Rasmussen 182/145 3,378,101 4/1968 Zeitler 3,493,0792/1970 Dudschus ..182/63 3,576,233 4/1971 Thatcher 182/ 145 PrimaryExaminer-Reinaldo P. Machado Attorney-Henderson & Strom [5 7] ABSTRACTDescribed herein is a portable, vertically adjustable, scaffold. Thisscaffold comprises a base, a telescoping mast hingeably attached theretoand a platform. The telescoping mast is raised by a hydraulic hoist andthe mast is rotated about its lower end with a hydraulic hoist. As thetelescoping mast is raised, a cable secured to the mast raises theplatform assembly along the mast. Outriggers are provided to addstability to the scaffold.

8 Claims, 9 Drawing Figures Patented May 30, 1972 2 Sheets-Sheet l IPatented May 30, 1972 3,666,046

2 Sheets-Sheet 2 :4: 6 Mmswmz Mm A390.

BACKGROUND OF THE INVENTION This invention relates to a portable,vertically adjustable, scafiold which can be readily mounted on a pickuptruck.

Portable scaffolds can be used for a wide variety of purposes. They areessential in building construction, in maintenance of street lights,window washing, etc. For many years, inventors have searched for a trulyportable scaffold. These attempts are documented in Wille, U.S. Pat. No.3,367,448; Bergman, U.S. Pat. No. 3,l78,048; Wiegand, U.S. Pat. No.3,003,584; Smith, U.S. Pat. No. 3,232,377; Aune, U.S. Pat. No.2,423,167; and Dudscus, U.S. Pat. No. 3,493,079.

Although all of these scaffolds serve a useful purpose, they do not meetthe requirements of simplicity, low cost, and ease of portability. Thepresent invention provides a simple, economical, easily portablescaffold that can be mounted on a pickup truck or can be used by itselfwith a minimum of conversion time. The scaffold is readily mounted on orremoved from a pickup truck.

SUMMARY OF THE INVENTION This invention relates to a portable,vertically adjustable scaffold comprising a base means, a telescopingmast having an inside and an outside elongated tube, the inside tubebeing rotatably attached at its lower end to the base means, the masthaving a hydraulic means for raising the outside tube in slidingengagement with the inside tube. A second hydraulic means is providedfor rotating the mast about the lower end of the inside tube. Theplatform is arranged for vertical guiding movement on the mast when themast is in the vertical position and the platform is raised and loweredby means of cables secured to the mast and to the platform. When theoutside tube is raised, the platform is also raised.

It is an object of this invention to provide a portable scaffold ofnovel construction which is economical to build and readily portable.

Another object is to provide a portable scaffold having a telescopingmast hingeably secured to the base.

A further object is to provide a portable scaffold which can readily bemounted on or removed from a pickup truck.

Yet another object is to provide a scaffold having a foldable mast whichcan be folded quickly and easily.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a pickuptruck having the portable scaffold of this invention mounted thereonwith the mast in folded position.

FIG. 2 is a side view of the portable scafiold of this invention mountedon a pickup truck with the mast in a raised position.

FIG. 3 is an enlarged side view of the portable scaffold of thisinvention illustrating, in phantom, the platform assembly in raisedposition.

FIG. 4 is a perspective view of the forward end of the portable scaffoldwith the top of the mast cut away.

FIG. 5 is a cross-sectional side view of the portable scafi'old takenalong line 5-5 of FIG. 4 showing the locking arm in engagement with themast.

FIG. 6 is a side view of the platform assembly in guiding engagementwith the mast. Portions of the platform assembly are cut away to showthe wheels which contact the mast and guide the platform. 1

FIG. 7 is a cross-sectional front view of the upper portion of theplatform assembly taken along 7-7 of FIG. 6.

FIG. 8 is a top view of the platform assembly taken along line 8-8 ofFIG. 6 and showing the mast in cross-section.

FIG. 9 is a schematic of the hydraulic system of the portable scaffold.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,the portable scafi'old of this invention is generally indicated at 11 inFIGS. 1-3. The portable scaffold 11 is comprised of a base means 12(FIGS. 3-5 a telescoping mast 13 (FIG. 3) having an inside tube 14 andan outside tube 16 with a first hydraulic means 17 connected thereto. Asecond hydraulic means 18 is secured to the mast 13 for rotating themast 13 about its lower end. A platform assembly 19 supported by cables21 is arranged for vertical guiding movement on the outside tube 16 whenthe mast 13 is in a vertical position.

More specifically, the base means 12 (FIGS. 3-5) is preferably comprisedof l-beams 22 disposed at right angles in the same horizontal plane andrigidly secured together. The lbeams 22 generally are arranged inrectangular configuration but many other configurations can be utilized.Preferably, the base means 12 is of such a size that it can readily beplaced in a standard pickup truck 23 as illustrated in FIGS. 1 and 2.

Two angle members 24 and 26 (FIG. 4) are secured between opposite sidesof the base means 12. The lower end 27 of the hydraulic cylinder 28 ofthe second hydraulic means 18 is rotatably supported by a pin 29 securedto cross members 31 and 32 which in turn are secured to the anglemembers 24 and 26.

Longitudinal struts 33 (FIGS. 3 and 4) are rigidly connected between thefront I-beams 34 and the forwardmost angle member 24. A heavy duty hinge36 is secured to the front I- beam 34 and, additionally, is secured tothe longitudinal struts 33.

The mast 13 (FIG. 3) comprises an inside tube 14, an outside tube 16,and a first hydraulic cylinder 17. The inside tube 14 is hingeablysecured to hinge 36 at its lower end 37 and is rotatable therearound.The inside tube 14 can be of any configuration in cross-section but,preferably, is square or rectangular. The length of the inside tube 14is not critical but preferably is about the length of the box of anordinary pickup truck. Depending on the particular use desired, theinside tube 14 can be either longer or shorter. On the forward side 38of the inside tube 14, a bar 39 is horizontally disposed which mateswith a latching arm 40 secured to the front I-beam 34. Proximate thelower end 37 of the inside tube 14 and on the rearward side 41, a lug 42is formed for rotatably securing the upper end 43 of the hydrauliccylinder 38 thereto.

The outside tube 16 (FIG. 3) is of the same general configuration andlength as the inside tube 14. The outside tube 16 should be slightlylarger in inside diameter than the inside tube 14 is in outsidediameter. Therefore, the outside tube 16 mates over the inside tube 14and is slidingly engaged therewith. The outside tube 16 is hollow andopen on both ends 44 and 46. At the upper end 46, two pulleys 47 arerotatably secured by axle 48 The first hydraulic means 17 (FIGS. 3 and9) comprises an elongate hydraulic cylinder 49. The cylinder 49 isdisposed within the inside tube 14 and is secured at its lower end 51 tothe inside tube 14 proximate the lower end 37 of the inside tube 14. Theupper end 52 of the cylinder 49 is secured to a plate 53 rigidly securedhorizontally proximate the upper end 44 of the outside tube 16. Theplate 53 is provided with apertures 54 through which cables 21 can pass.Hydraulic fluid is supplied to the cylinder 49 by a pump 56 through atwo-way valve 57.

A latching arm 40 (FIGS. 3 and 4) is secured on the front beam 34 and issecurable with bar 39. The latching arm 40 is rotatably secured onforwardly extending lug 58 mounted on the front I-beam 34. Mechanicallinkage 59 (FIG. 4) is utilized to release and/or lock the latching arm40 in engagement with bar 39. The latching arm 40 is matable with thebar 39 only when the mast 13 is in an upright or vertical position.

The second hydraulic means 18 (FIG. 3), as indicated previously, is ahydraulic cylinder 28 rotatably connected to the inside tube 14 of themast l3 and to the base means 12 and is utilized to rotate the mast 13about the lower end 37 of the inside tube 14 between an essentiallyhorizontal position and a vertical position. The twoway valve 57 and thepump 56 supply hydraulic fluid to the cylinder 28 and control the flowof hydraulic fluid thereto.

The two-way valve 57 is mechanically connected to the latching arm 39 byarm 60 (FIG. When the mast 13 is in a vertical position and locked inposition, hydraulic fluid flows only into the first hydraulic cylinder49 and the fluid in the second hydraulic cylinder 28 is sealed thereinthereby locking the second hydraulic cylinder 28. When the latching arm39 is in the release position, hydraulic fluid flows only into thesecond hydraulic cylinder 28.

The platform assembly 19 (FIGS. 3 and 6) is arranged for verticalguiding movement along the outside tube 16. The platform assembly 19comprises a deck 61 disposed rearwardly of the mast 13 when the mast 13is in a vertical position. The deck 61 is generally of rectangularconfiguration. A series of lateral bars 62 and longitudinal bars 63comprise the superstructure and these bars 62 and 63 are covered withdecking material 64. Guard rails 65 are dcmountably secured around thesides of the deck 61. Centering guides 66 are formed on the bottom 67 ofthe deck 61 and secure the platform assembly 19 from moving horizontallywhen the mast 13 is in its folded position.

Two vertical struts 68 and 69 (FIGS. 3, 6 and 8) of L- shapedconfiguration are secured to the forward edge 71 of the deck 61 andextend upwardly of the deck 61 on opposing sides of the mast 13.

A plurality of wheel means 73 or rollers are secured to the platformassembly 19 for guiding the platform assembly 19 vertically along theoutside tube 16 of the mast 13. The rollers 73 are disposed on all foursides of the mast 13.

The forward roller 74 (FIGS. 6 and 7) is supported on an axle 76 joiningthe top and forwardmost portions 77 of the L- shaped struts 68 and 69and is in constant contact with the outside tube 16 when the mast 13 isin an upright position. Side rollers 78 are secured to the struts 68 and69 and rollingly engage the sides of the outside tube 16. The rearroller 79 is secured to the deck 61 and contacts the rearward side ofthe outside tube 16. The mast 13 can readily be folded into thehorizontal position without disengaging or otherwise manipulating any ofthe rollers 73.

At least one cable 21, and preferably two cables 21, secure the platformassembly 19 to the mast 13 (FIG. 3). One end 81 of the cables 21 issecured to the deck 61 by means of side straps 72 on each side of themast. The cables 21 extend upwardly and over the pulleys 47 secured tothe top 46 of the outside tube 16. The cables 21 then extend downwardlythrough the outside tube 16, through the apertures 54 in plate 53 andare secured, at the other end 82, to the inside tube 14. As the outsidetube 16 is raised, the platform assembly 19 is raised twice as far asthe outside tube 16.

The hydraulic pump 56 is controlled from the platform assembly as shownin FIG. 2. An electrical line 83 secured on the platform assembly 19 isutilized to control the raising and lowering ofthe platform assembly 19.

Outrigger means 84 of novel construction are secured to the base means12. The outrigger means 84 comprises arcuate, 90, arms 86 and 87extending outwardly of opposite sides of the portable scaffold 11. Thearms 86 and 87 are slidingly engaged with the base means 12 by clampmeans 88.

Each of the clamp means 88 (FIG. 4) is comprised of the flat, widenedend 89 of the arm 86 and 87, a spacer 91 and a bottom widened member 92.The clamp means 88 is secured together by nuts and bolts 93. The nutsand bolts 93 can be loosened to render the clamp means 88 in slidingengagement with the front I-beam 34.

The other end 94 (FIG. 4) of the arms 86 and 87 is comprised of anattachment cylinder 96. Two holes are formed through the attachmentcylinder 96 to secure the jack extensions 97 in either a verticalposition or in a horizontal position.

The jack extensions 97 (FIG. 4) are similar to those jacks used onpickup campers. The foot 98 may be turned down or up manually orelectrically and is capable of reaching the ground and stabilizing thescaffold 11. A hollow attachment cylinder 99 is formed on the jackextensions 97 and mates with the first attachment cylinder 96.

If it is desired to use the scaffold 11 without the truck 23, the arms86 and 87 can be secured to the bottom portion 10 of the I-beams 22 andwheels (not shown) can be secured to the first attachment cylinder 96.

The outrigger means 84 can be utilized to load and unload the scaffoldfrom the truck 23. A third outrigger (not shown) can simply be attachedto the mast 13 in folded position or to the rear of the base means 12.The scaffold 11 can then be easily raised and/or lowered.

In a second embodiment of this invention, two masts 13 can be utilized,one on each end of the base means 12. The operation of the scaffold 11is exactly the same except the rearward mast 13 folds forwardly ratherthan rearwardly. By using this construction, heavier loads can be raisedand lowered.

Although a preferred embodiment has been described, it is to beremembered that various modifications may be made without departing fromthe invention as defined in the appended claims.

I claim:

1. A portable, vertically adjustable, scaffold comprising:

base means;

a telescoping mast having an inside, elongated tube hingeably attachedat the lower end thereof to said base means and rotatable about saidlower end from an essentially horizontal position to a verticalposition; an outside, elongated tube mating over said inside tube andslidingly engaged with said inside tube; and first hydraulic meanssecured to said inside tube and connected to said outside tube forraising said outside tube relative to said inside tube;

second hydraulic means for rotating said mast about said lower endofsaid inside tube;

a platform assembly arranged for vertical guiding movement along saidoutside tube when said mast is in a vertical position;

at least one cable having two ends, one of said ends being secured tosaid platform and the other of said ends being secured to said mast sothat said platform is raised when said outside tube is raised; and

outrigger means adjustably secured to said base means for addingstability to said vertically adjustable scaffold.

2. The portable scaffold of claim 1 wherein said first hydraulic meansis disposed inside said inside tube.

3. The portable scaffold of claim 1 wherein a locking arm is rotatablysecured to said base means, said locking arm secu rable to said mastwhen said mast is in an upright position.

4. The portable scaffold of claim 3 wherein a two-way valve controls theflow of hydraulic fluid into said first hydraulic means and said secondhydraulic means, said two'way valve being mechanically connected to saidlocking arm and allowing hydraulic fluid to flow into said firsthydraulic means only when said locking arm is secured to said mast andallowing hydraulic fluid to flow into said second hydraulic means onlywhen said locking arm is not secured to said mast.

5. The portable scaffold of claim 4 wherein said platform assemblycomprises:

a platform deck disposed rearwardly of said mast when said mast is in avertical position;

two vertical struts of inverted L-shaped configuration secured to saiddeck on opposite sides of said mast;

a plurality of wheel means secured to said deck and said struts forguiding said platform deck vertically along said outside tube of saidmast.

6. The portable scaffold of claim 5 wherein at least one pulley issecured proximate the upper end of said outside tube;

one end of said cable is secured to the platform deck by side strapmeans, and said other end of said cable is secured proximate the upperend of said inside tube, said cable passing upwardly through saidoutside tube and around said pulley to said side strap means. 7. Theportable scaffold of claim 6 wherein said base means comprises l-beamsdisposed at right angles and rigidly secured together.

8. The portable scaffold of claim 7 wherein said outrigger meanscomprises:

arcuate arms slidably secured on opposite sides of said

1. A portable, vertically adjustable, scaffold comprising: base means; a telescoping mast having an inside, elongated tube hingeably attached at the lower end thereof to said base means and rotatable about said lower end from an essentially horizontal position to a vertical position; an outside, elongated tube mating over said inside tube and slidingly engaged with said inside tube; and first hydraulic means secured to said inside tube and connected to said outside tube for raising said outside tube relative to said inside tube; second hydraulic means for rotating said mast about said lower end of said inside tube; a platform assembly arranged for vertical guiding movement along said outside tube when said mast is in a vertical position; at least one cable having two ends, one of said ends being secured to said platform and the other of said ends being secured to said mast so that said platform is raised when said outside tube is raised; and outrigger means adjustably secured to said base means for adding stability to said vertically adjustable scaffold.
 2. The portable scaffold of claim 1 wherein said first hydraulic means is disposed inside said inside tube.
 3. The portable scaffold of claim 1 wherein a locking arm is rotatably secured to said base means, said locking arm securable to said mast when said mast is in an upright position.
 4. The portable scaffold of claim 3 wherein a two-way valve controls the flow of hydraulic fluid into said first hydraulic means and said second hydraulic means, said two-way valve being mechanically connected to said locking arm and allowing hydraulic fluid to flow into said first hydraulic means only when said locking arm is secured to said mast and allowing hydraulic fluid to flow into said second hydraUlic means only when said locking arm is not secured to said mast.
 5. The portable scaffold of claim 4 wherein said platform assembly comprises: a platform deck disposed rearwardly of said mast when said mast is in a vertical position; two vertical struts of inverted L-shaped configuration secured to said deck on opposite sides of said mast; a plurality of wheel means secured to said deck and said struts for guiding said platform deck vertically along said outside tube of said mast.
 6. The portable scaffold of claim 5 wherein at least one pulley is secured proximate the upper end of said outside tube; one end of said cable is secured to the platform deck by side strap means, and said other end of said cable is secured proximate the upper end of said inside tube, said cable passing upwardly through said outside tube and around said pulley to said side strap means.
 7. The portable scaffold of claim 6 wherein said base means comprises I-beams disposed at right angles and rigidly secured together.
 8. The portable scaffold of claim 7 wherein said outrigger means comprises: arcuate arms slidably secured on opposite sides of said portable scaffold and extending outwardly thereof, each of the outer ends of said arcuate arms terminating in an attachment cylinder; jack extensions secured on said attachment cylinders and rotatable thereon; said jack extensions capable of reaching the ground when said portable scaffold is mounted on a truck. 